It is commonplace nowadays for people to use public Wi-Fi and wireless networks to connect to data networks, such as the internet, or local servers. This is accomplished by the provision of a wireless network adapter (most commonly, a Wi-Fi adapter) installed on a device, such as a mobile telephone, laptop computer, tablet PC etc., which connects to the LAN or WAN via an access point. The data transfer speed of the wireless connection is limited by a number of factors, which ultimately determine the download and upload speed of data from, and to, the LAN or WAN, respectively.
Ultimately, the data transfer speed is limited by the speed of the network, for example whether it is a 10 Mbps, 100 Mbps or 1000 Mbps (or greater) network and this is determined by the speed of the switches, routers and other devices connected to the network. The network is connected to a wireless access point (hereinafter an “AP”), which bridges the hard-wired LAN to the wireless LAN (WLAN) and wireless devices can thus connect to the AP to establish a connection to the LAN.
The speed of the WLAN is determined by a number of factors, such as the distance between the wireless device and the AP (signal strength diminishing with distance), the physical layout of the environment (e.g. the location of attenuating and/or reflecting elements, such as walls, floors and ceilings), and the number of concurrently connected users. Whilst the former factors that determine the maximum possible download speed are largely outside the WLAN provider's control, the number of concurrent users is, in many cases, within the WLAN provider's control.
The number of concurrent connections to a WLAN AP is important because the maximum available bandwidth, i.e. the bandwidth at the AP-LAN connection, and the bandwidth of AP, must effectively be shared between the concurrent users. Thus, a single user may be able to make full use of the available bandwidth, but when another user connects to the same AP, the bandwidth for each user is effectively halved. In practice this is not always the case because data upload and download for concurrent users is not necessarily simultaneous, i.e. the bandwidth can be striped such that each user attains the maximum bandwidth, albeit at different times. However, when many users connect to a single AP, the bandwidth, and hence the data download/upload speeds can be adversely affected.
APs are nowadays available that have multi-in, multi-out (MIMO) capabilities, and these APs often have multiple antennae, which enable some of the aforementioned problems to be ameliorated. However, up-scaling existing MIMO APs is difficult (there is currently a limit to the number of MIMO connections that can be made to a single MIMO AP), and installing multiple APs in a single location can be problematic also.
The reason for this is that to establish a WLAN connection, a user typically needs to pass a security protocol, such as WPA, WPS and WEP before a connection to the WLAN can be established which usually requires a user to correctly enter a password corresponding to the unique identification (SSID) of the AP to gain access to it. Specifically, each AP is usually given a SSID, and its own password, and this is a sensible precaution to prevent data collisions and DNS errors on the network. This is also sensible where (as the case most often); connections to the WLAN are established on the basis of an IP address of the AP, rather than on the basis of its truly unique MAC.
For the sake of convenience, AP connection credentials (SSID and password) are often stored on users' devices for a period of time so that when the device comes back within range of an AP to which it has previously successfully connected, a WLAN connection can be initiated automatically—without any user intervention.
In order to scale-up the available bandwidth, it is nowadays becoming more common to install multiple APs in heavily-used WLAN environments.